FRIDAY, AUGUST 21
■ This evening look for Antares about a fist at arm’s length to the right of the Moon, as shown below. A lesser distance farther right shines Delta Scorpii, the second-brightest star of upper Scorpius.
SATURDAY, AUGUST 22
■ As August proceeds and nights begin to turn chilly, the Great Square of Pegasus looms up in the east, balancing on one corner. Its stars are only 2nd and 3rd magnitude. Your fist at arm’s length fits inside it.
From the Square’s left corner, the backbone of the constellation Andromeda extends to the lower left: three stars (including the corner) in a slightly curving line, about as bright as those forming the Square. Extend the line farther and you can add Alpha Persei.
A version of this whole enormous pattern was named “the Andromegasus Dipper” by the late Sky & Telescope columnist George Lovi. It’s shaped much like a giant Little Dipper with an extra-big bowl. It’s currently lifting upward.
■ The actual Little Dipper, meanwhile, is tipping over leftward in the north. It’s less than a third as long as the Andromegasus Dipper as drawn above, and most of it is much fainter. As always, you’ll see that the Little Dipper is oriented more than 90° counterclockwise compared to Andromegasus. It’s now dumping its contents out.
SUNDAY, AUGUST 23
■ Late these evenings as autumn approaches, Fomalhaut, the Autumn Star, makes its inevitable appearance above the southeast horizon. Its rising time will depend on where you live. But by about 11 p.m. now, you should have no trouble identifying it low in the southeast if you have a good view in that direction. No other 1st-magnitude star is anywhere near it.
To locate Fomalhaut, or to see where it will rise, follow the diagonal line of the west (upper right) side of the Great Square of Pegasus down toward the lower right by about four fists at arm’s length.
Saturn, similarly bright but glowing more steadily, is about a fist and a half below the Great Square, as shown above.
MONDAY, AUGUST 24
■ Another sign of the advancing season: Cassiopeia is high in the northeast, its W pattern tilting up as shown above. Below it, starry Perseus is reaching up.
The highest part of Perseus includes the wintry Double Cluster. To find it, look below the lowest two stars of the Cassiopeia W (they’re the faintest two), by somewhat more that the distance between them. You’re looking for what seems like a small spot of enhanced Milky Way glow. For practice, follow this route on the image above.
Binoculars or a finderscope will help you detect the Double Cluster even through a fair amount of light pollution. The pair are a glory in a telescope.
TUESDAY, AUGUST 25
■ How soon after sunset can you see the big Summer Triangle? Face east. Vega, the Triangle’s brightest star, is nearly at the zenith (for skywatchers at mid-northern latitudes). Deneb is the first bright star to Vega’s east-northeast. Altair shines less high in the southeast.
WEDNESDAY, AUGUST 26
■ This evening look about three fists above the Moon, and maybe a bit right, for 1st-magnitude Altair. As evening grows late, watch for rising Fomalhaut two fists in the opposite direction from the Moon.
THURSDAY, AUGUST 27
■ Full Moon tonight. An almost total eclipse of the Moon will occur for most of the Americas! Skywatchers in the eastern half of North America can watch the entire eclipse from start to finish. Westerners will see the partially eclipsed Moon rise at sunset in the evening (August 27th), with the deepest stage at mideclipse still to come.
In the Northwest, sunset and moonrise will happen somewhat after the deepest stage has already passed. See world map.
Timetable in Eastern Daylight Time (EDT), which is UT minus 4 hours. Convert to your own time zone:
Partial eclipse begins: 10:34 p.m. EDT
Mid-eclipse: 12:13 a.m. EDT, when 93% of the Moon’s diameter will be covered.
Partial eclipse ends: 1:52 a.m. EDT
Slight shading by the penumbra of Earth’s shadow will be visible on the Moon for about 40 minutes before partial eclipse begins and the same after partial eclipse ends.
FRIDAY, AUGUST 28
■ As summer progresses and Arcturus moves down the western sky, the kite figure of Boötes that sprouts up from Arcturus tilts to the right (depending on your latitude). The kite is narrow, slightly bent, and 23° long: about two fists at arm’s length. Arcturus is its bottom point where the stubby tail is tied on.
The Big Dipper poses to the right in the northwest at about the same height as Arcturus, as shown below.
SATURDAY, AUGUST 29
■ A winter preview: Step out before the first light of dawn any time this coming week, and the sky displays the same starry panorama that it will at dinnertime around New Year’s. Orion will be striding up in the southeast, with Aldebaran and then the Pleiades high above it. Sirius sparkles far down below Orion. The Gemini twins are lying on their sides well up in the east.
Even Saturn, slow mover among planets, will be located almost the same then as in pre-dawn now: under the Great Square of Pegasus high in the south-southwest.
SUNDAY, AUGUST 30
■ The waning gibbous Moon rises in the east in late twilight. Saturn follows it up about 30 minutes later. Another hour and they’re nicely high free and clear.
Although they look close together, Saturn is currently 3,400 times farther away — and it’s 35 times bigger in diameter than the Moon, not even counting the rings. Nowhere in human experience but astronomy are things so different than they appear. It took many millennia to figure that out!
■ The end of August means that Scorpius, which was the proud starring constellation in the south on July evenings, is now tilting over and lying down in the southwest after dark, preparing to bed down and drift off for the season.
This Week’s Planet Roundup
Mercury is hidden in conjunction with the Sun.
Venus continues to shine brightly (magnitude –4.5) as the “Evening Star” low in the west in twilight. It now sets a few minutes before twilight’s end.
Fainter Spica, less than 1% as bright, is closing in on Venus from the left or upper left. They’re 10° apart on Friday August 21st and 3½° apart by Friday the 28th. Their conjunction will come on September 1st, when they’ll shine 1½° from each other.
In a telescope Venus is a very thick crescent only a little less than half-lit, and 27 arcseconds from pole to pole. Catch it as soon in late afternoon or early dusk as you can, before it sinks low into poorer seeing. Venus will remain in twilight view until the end of the summer, gradually lower, enlarging while waning in phase.
Mars (magnitude +1.3, in Gemini by the foot of the Castor stick figure) rises around 2 a.m. daylight-saving time. By the beginning of dawn you’ll find it glowing high in the east to the right of Pollux and Castor.
Since Mars is on the far side of its orbit from us, in a telescope it’s still just a tiny, fuzzy blob 5 arcseconds wide.
Jupiter (magnitude –1.8, in dim Cancer) rises around the very beginning of twilight. As dawn brightens, look for it glowing steadily low in the east-northeast.
Saturn (magnitude +0.5, at the Pisces-Cetus border) rises in the east around the end of twilight. Look for it about a fist and a half below the Great Square of Pegasus (which is balancing on one corner). Saturn is best placed for telescopic viewing high in the south in the early-morning hours.
A few telescopic reports of these subtle, transient features date from the 19th century. The first systematic study of them was done by Sky & Telescope‘s Stephen James O’Meara, a famously eagle-eyed visual observer, using Harvard Observatory’s 9-inch Clark refractor starting in 1977. Spacecraft flybys later confirmed them in detail.
The spokes remain something of a mystery. Says Wikipedia, “The leading hypothesis… is that they consist of microscopic dust particles suspended away from the main ring by electrostatic repulsion, [because] they rotate almost synchronously with the magnetosphere of Saturn,” not with the ring material itself Electrons in the solar wind, as redirected by Saturn’s magnetic field, may be involved. “The precise mechanism generating the spokes is still unknown.”
Uranus (magnitude 5.7, in Taurus) lurks halfway between the Pleiades and Aldebaran in the early morning sky.
Neptune (magnitude 7.8, at the Pisces/Cetus border) lurks deeper 10° west of Saturn. You’ll need detailed finder charts to tell Uranus and Neptune from stars of similar brightnesses.
All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world’s mid-northern latitudes. Descriptions and graphics that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) is Universal Time minus 4 hours. UT is also known as UTC, GMT, or Z time.
Want to become a better astronomer? Learn your way around the constellations. They’re the key to locating everything fainter and deeper to hunt with binoculars or a telescope.
This is an outdoor nature hobby. For a more detailed constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.
For the attitude every amateur astronomer needs, read Jennifer Willis’s Modest Expectations Give Rise to Delight.
Once you get a telescope, to put it to good use you’ll want a much more detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas, in either the original or Jumbo Edition. Both show all 30,000 stars to magnitude 7.6, and 1,500 deep-sky targets — star clusters, nebulae, and galaxies — to search out among them.
Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many, as well as many more deep-sky objects. It’s currently out of print, but maybe you can find one used.
The next up, once you know your way around well, are the even larger Interstellarum Deep-Sky Atlas (with 201,000+ stars to magnitude 9.5 and 14,000 deep-sky objects selected to be detectable by eye in very large amateur telescopes), and Uranometria 2000.0 (332,000 stars to mag 9.75, and 10,300 deep-sky objects).
For the necessary tricks, read How to Use a Star Chart with a Telescope. It applies just as much to electronic charts on your phone or tablet — which many observers find handier and more versatile, if sometimes less well designed and contextualized.
You’ll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham’s Celestial Handbook. It was my bedside reading for years. An impressive more modern one is the big Night Sky Observer’s Guide set (2+ volumes) by Kepple and Sanner. The pinnacle for total astro-geeks is the new Annals of the Deep Sky series, currently at 11 volumes as it works its way forward through the constellations alphabetically. So far it’s up to H.
Can computerized telescopes replace charts? Well, I used to say this:
“Not for beginners, I don’t think, unless you prefer spending your time getting finicky technology to work rather than learning how to explore through the sky yourself. As Terence Dickinson and Alan Dyer say in their Backyard Astronomer’s Guide, ‘A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand and a curious mind.’ Without these, ‘the sky never becomes a friendly place.’ “
But things change. The technology has continued to improve and become more user-friendly — particularly with “plate solving” software that can now recognize any star field to determine exactly where the telescope is pointed — finally bypassing all aiming imperfections in the mount, tripod, gears, bearings and other mechanics, or in the user’s skill in setting up.
The latest revolution is the rise of small, photography-only “smartscopes.” These take advantage of not only today’s pointing technology, but also the vastly better capabilities of imaging chips and image processing compared to the human retina and visual cortex. The most sophisticated image stacking and processing can come built right in. The result is decent deep-sky imaging from shockingly small units, relatively low priced. The image may be viewable on your phone or computer as it builds up in real time. Some can directly enable contributions to citizen-science projects.
Smartscopes are changing the hobby at the entry level. For more on this see Richard Wright’s “The Rise of the Smart Telescopes” in the November 2025 Sky & Telescope. And read the magazine’s review of this especially small one.
If you get a larger, more conventional computerized scope that you can look through, make sure that its drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).
Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty’s monthly
podcast tour of the naked-eye heavens above. It’s free.
“The dangers of not thinking clearly are much greater now than ever before. It’s not that there’s something new in our way of thinking, it’s that credulous and confused thinking can be much more lethal in ways it was never before.”
— Carl Sagan, 1996, The Demon-Haunted World: Science as a Candle in the Dark
“Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence.”
— John Adams, 1770, in the summation of his unpopular, but successful, defense of British soldiers in the Boston Massacre trial
“Truly, whoever can make you believe absurdities can make you commit atrocities.”
— Voltaire, 1765, Questions sur les miracles
1. Every month the whole celestial sphere, as seen from our orbiting Earth, turns 15° westward with respect to the Sun. So when the waxing Moon passes the same star each month, it too is 15° farther west with respect to the Sun. That means 15° closer to our line of sight to the Sun. So, we see the waxing Moon at a thinner phase each time it passes the same star in the evening sky.
The opposite happens to the waning Moon, best seen in in the morning sky: It gets thicker at each successive monthly conjunction with a star.